I've long since given up pretending I can identify exact model years for old BMWs, and this one in particular seems especially challenging. Judging by all the decals on this BMW and the other vintage German machinery that lives at the same household, this car's owner appears to be the sort of hardcore car freak who doesn't hesitate to swap body panels and bumpers around when he or she scores some good components (note the different side-marker configurations on the right and left front fenders, for example). I'm going to say it's a '71.